What if you could train plants for national security? A biologist at Colorado State University working with the Department of Defense is doing just that. Genetic engineering is making plants react to threats they never encountered in nature -for human benefit.

Picture this at an airport, perhaps in as soon as four years: A terrorist rolls through the sliding doors of a terminal with a bomb packed into his luggage (or his underwear). All of a sudden, the leafy, verdant gardenscape ringing the gates goes white as a sheet. That’s the proteins inside the plants telling authorities that they’ve picked up the chemical trace of the guy’s arsenal.

It only took a small engineering nudge to deputize a plant’s natural, evolutionary self-defense mechanisms for threat detection. “Plants can’t run and hide,” says June Medford, the biologist who’s spent the last seven years figuring out how to deputize plants for counterterrorism. “If a bug comes by, it has to respond to it. And it already has the infrastructure to respond.”

That would be the “receptor” proteins in its DNA, which respond naturally to threatening stimuli. If a bug chews on a leaf, for instance, the plant releases a series of chemical signals called terpenoids — “a cavalry call,” Medford says, that thickens the leaf cuticle in defense.

So far, plants have been produced that react to the presence of TNT, but other factors, such as light and movement, interfere with the process. Medford thinks a working plant is still three or four years away. Link -via Fortean Times